Late gadolinium-enhanced cardiovascular magnetic resonance identifies patients with standardized definition of ischemic cardiomyopathy: A single centre experience

Multicentre medicoeconomic evaluation of cardiac magnetic resonance imaging for predicting coronary artery disease in left ventricular dysfunction: The CAMAREC study design

BACKGROUND

Cardiac magnetic resonance imaging may provide a non-invasive alternative to coronary angiography for differentiating between ischaemic and non-ischaemic cardiomyopathy in cases of unexplained reduced left ventricular ejection fraction.

AIM

The CAMAREC study aims to evaluate the diagnostic accuracy of cardiac magnetic resonance imaging in predicting significant coronary artery disease in patients with reduced left ventricular ejection fraction, using coronary angiography as the gold standard for comparison.

METHODS

CAMAREC is a prospective cohort study of 406 patients in 10 centres with newly diagnosed, unexplained left ventricular ejection fraction ≤ 45%. Cardiac magnetic resonance imaging and coronary angiography will be conducted within a 2-week interval, starting with cardiac magnetic resonance imaging; independent committees will review the results blindly. Primary outcome is sensitivity of detecting ischaemic scar on cardiac magnetic resonance imaging for predicting significant coronary artery disease on coronary angiography according to Felker's criteria. Secondary outcomes include specificity and positive and negative predictive values (with 95% confidence intervals) of cardiac magnetic resonance imaging for predicting significant coronary artery disease in patients with reduced left ventricular ejection fraction, kappa concordance coefficient between cardiac magnetic resonance imaging and coronary angiography for diagnosing the affected myocardial territory, and the impact of cardiac magnetic resonance imaging on revascularization decisions. Two ancillary studies will evaluate the incremental cost-effectiveness of using cardiac magnetic resonance imaging first versus coronary angiography first, and the sensitivity of pre- and postcontrast T1-mapping for predicting significant coronary artery disease in patients with reduced left ventricular ejection fraction.

CONCLUSION

Our study protocol is designed to rigorously evaluate cardiac magnetic resonance imaging as a non-invasive alternative to coronary angiography in patients with unexplained reduced left ventricular ejection fraction. The results will have significant implications for patient management, and may support growing evidence for the clinical utility of cardiac magnetic resonance imaging.

Accuracy of cardiac magnetic resonance imaging to rule out significant coronary artery disease in patients with systolic heart failure of unknown aetiology: Single-centre experience and comprehensive meta-analysis

BACKGROUND

Coronary artery disease (CAD) is the leading cause of systolic heart failure (HF). Cardiac magnetic resonance imaging (CMR) is a non-invasive technique that detects a myocardial infarction scar as subendocardial or transmural late gadolinium enhancement (st-LGE).

AIM

We sought to evaluate whether a lack of st-LGE could rule out CAD in new-onset systolic HF of unknown aetiology.

METHODS

We included 232 consecutive patients with new-onset HF and left ventricular ejection fraction ≤35% who underwent both coronary angiography and CMR to assess HF aetiology. CAD was defined as the presence of coronary artery stenosis≥50% on a coronary angiogram. We assessed sensitivity, specificity, and positive and negative likelihood ratios (PLR and NLR) of the presence of st-LGE to detect underlying CAD. A complementary meta-analysis of 11 studies (including ours) was also performed.

RESULTS

In our study, 49 (21.1%) patients had CAD. The sensitivity and specificity of the presence of st-LGE to detect CAD were 69 and 92%, respectively. PLR and NLR were 8.47 and 0.33, respectively. In the meta-analysis, 1227 patients were included, and the prevalence of CAD ranged from 19.2 to 68.3%. Sensitivity, specificity, PLR and NLR were 87% (95% confidence interval [CI] 0.80-0.92), 93% (95% CI 0.89-0.96), 12.91 (95% CI 7.70-21.64) and 0.14 (95% CI 0.09-0.22), respectively. Altogether, 55 patients presented CAD with no st-LGE; inversely, 75 patients presented st-LGE with no CAD.

CONCLUSION

With a CMR specificity of 93%, the absence of st-LGE rules out significant underlying CAD in patients with systolic HF of unknown aetiology in most cases.

Concordant and Discordant Cardiac Magnetic Resonance Imaging Delayed Hyperenhancement Patterns in Patients with Ischemic and Non-Ischemic Cardiomyopathy

Background and Objectives

The diagnosis of ischemic (ICM) and non-ischemic cardiomyopathy (NICM) is conventionally determined by the presence or absence of coronary artery disease (CAD) in the setting of a reduced left systolic function. However the presence of CAD may not always indicate that the actual left ventricular (LV) dysfunction mechanism is ischemia, as other non-ischemic etiologies can be responsible. We investigated patterns of myocardial fibrosis using delayed hyperenhancement (DHE) on cardiac magnetic resonance (CMR) in ICM and NICM.

Subjects and Methods

Patients with systolic heart failure who underwent a CMR were prospectively analyzed. The heart failure diagnosis was based on the modified Framingham criteria and LVEF <35%. LV dysfunction was classified as ICM or NICM based on coronary anatomy.

Results

A total of 101 subjects were analyzed; 34 were classified as ICM and 67 as NICM. The DHE pattern was concordant with the conventional diagnosis in 27 (79.4%) of the patients with ICM and 62 (92.5%) of the patients with NCIM. A discordant NICM DHE pattern was present in 8.8% of patients with ICM, and an ICM pattern was detected 6.0% of the patients with NICM. Furthermore, 11.8% of the patients with ICM and 1.5% of those with NICM demonstrated a mixed pattern.

Conclusion

A subset of patients conventionally diagnosed with ICM or NICM based on coronary anatomy demonstrated a discordant or mixed DHE pattern. CMR-DHE imaging can be helpful to determine the etiology of heart failure in patients with persistent LV systolic dysfunction.

Diagnostic Accuracy of Cardiac Magnetic Resonance Imaging in the Evaluation of Newly Diagnosed Heart Failure With Reduced Left Ventricular Ejection Fraction

The aim of this study was to determine the diagnostic value of cardiac magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE), cine imaging, and resting first-pass perfusion (FPP) in the evaluation for ischemic (IC) versus nonischemic (NIC) cardiomyopathy in new-onset heart failure with reduced (≤40%) left ventricular ejection fraction (HFrEF). A retrospective chart review analysis identified 83 patients from January 2009 to June 2012 referred for CMR imaging evaluation for new-onset HFrEF with coronary angiography performed within 6 months of CMR. The diagnosis of IC was established using Felker criteria on coronary angiography. CMR sequences were evaluated for the presence of patterns suggestive of severe underlying coronary artery disease as the cause of HFrEF (subendocardial and/or transmural LGE, regional wall motion abnormality on cine, regional hypoperfusion defect on resting FPP). Discriminative power was assessed using receiver operator characteristics curve analysis. Coronary angiography identified 36 patients (43%) with IC. Presence of subendocardial and/or transmural LGE alone demonstrated good discriminative power (C-statistic 0.85, 95% confidence interval 0.76 to 0.94) for the diagnosis of IC. The presence of an ischemic pattern on both LGE and cine sequences resulted in a specificity of 87% for the diagnosis of IC, whereas the absence of an ischemic pattern on both LGE and cine sequences resulted in a specificity of 94% for the diagnosis of NIC. Addition of resting FPP on a subset of patients did not improve diagnostic values. In conclusion, CMR has potential value in the diagnostic evaluation of IC versus NIC.

Left ventricular geometric remodeling in relation to non-ischemic scar pattern on cardiac magnetic resonance imaging

Left ventricular (LV) remodeling and myocardial fibrosis have been linked to adverse heart failure outcomes. Mid wall late gadolinium enhancement (MW-LGE) on cardiac magnetic resonance (CMR) imaging is well-associated with non-ischemic cardiomyopathy (NICM), but prevalence in ischemic cardiomyopathy (ICM) and association with remodeling are unknown. The population comprised patients with systolic dysfunction [LV ejection fraction (LVEF ≤ 40 %)]. CMR was used to identify MW-LGE, conventionally defined as fibrosis of the mid-myocardial or epicardial aspect of the LV septum. 285 patients were studied. MW-LGE was present in 12 %, and was tenfold more common with NICM (32 %) versus ICM (3 %, p < 0.001). However, owing to higher prevalence of ICM, 15 % of patients with MW-LGE had ICM. LV wall stress was higher (p = 0.02) among patients with, versus those without, MW-LGE despite similar systolic blood pressure (p = 0.24). In multivariate analysis, MW-LGE was associated with CMR-quantified LV end-diastolic volume (p = 0.03) independent of LVEF and mass. Incorporation of clinical and imaging variables demonstrated MW-LGE to be associated with higher LV end-diastolic volume (OR 1.13, CI 1.004-1.27 per 10 ml/m(2), p = 0.04) after controlling for presence of NICM (OR 16.0, CI 5.8-44.1, p < 0.001). While more common in NICM, MW-LGE can occur in ICM and is a marker of LV chamber dilation irrespective of cardiomyopathic etiology.

The role of cardiac MR in new-onset heart failure

In patients with heart failure, cardiovascular magnetic resonance imaging (CMR) allows a multifaceted approach to cardiac evaluation by enabling an assessment of morphology, function, perfusion, viability, tissue characterization, and blood flow during a single comprehensive examination. Given its accuracy and reproducibility, many believe CMR is the reference standard for the noninvasive assessment of ventricular volumes, mass, and function, and offers an ideal means for the serial assessment of disease progression or treatment response in individual patients. Delayed-enhancement (DE)-CMR provides a direct assessment of myopathic processes. This permits a fundamentally different approach than that traditionally taken to ascertaining the etiology of cardiomyopathy, which is vital in patients with nonischemic cardiomyopathy and incidental coronary artery disease and patients with mixed, ischemic and nonischemic cardiomyopathy. Precise tissue characterization with DE-CMR also improves the diagnosis of left ventricular thrombus, for which it is the emerging clinical reference standard. There is a growing body of literature on the utility of CMR for patient risk stratification, and its potential role in important management decisions such as for cardiac resynchronization therapy and defibrillator placement.

Role of cardiovascular magnetic resonance as a gatekeeper to invasive coronary angiography in patients presenting with heart failure of unknown etiology

BACKGROUND

In patients presenting with new-onset heart failure of uncertain etiology, the role of coronary angiography (CA) is unclear. Although conventionally performed to differentiate underlying coronary artery disease from dilated cardiomyopathy, CA is associated with a risk of complications and may not detect an ischemic cause resulting from arterial recanalization or an embolic episode. In this study, we assessed the diagnostic accuracy of a cardiovascular magnetic resonance (CMR) protocol incorporating late gadolinium enhancement (LGE) and magnetic resonance CA as a noninvasive gatekeeper to CA in determining the etiology of heart failure in this subset of patients.

METHODS AND RESULTS

One hundred twenty consecutive patients underwent CMR and CA. The etiology was ascribed by a consensus panel that used the results of the CMR scans. Similarly, a separate consensus group ascribed an underlying cause by using the results of CA. The diagnostic accuracy of both strategies was compared against a gold-standard panel that made a definitive judgment by reviewing all clinical data. The study was powered to show noninferiority between the 2 techniques. The sensitivity of 100%, specificity of 96%, and diagnostic accuracy of 97% for LGE-CMR were equivalent to CA (sensitivity, 93%; specificity, 96%; and diagnostic accuracy, 95%). As a gatekeeper to CA, LGE-CMR was also found to be a cheaper diagnostic strategy in a decision tree model when United Kingdom-based costs were assumed. The economic merits of this model would change, depending on the relative costs of LGE-CMR and CA in any specific healthcare system.

CONCLUSION

This study showed that LGE-CMR is a safe, clinically effective, and potentially economical gatekeeper to CA in patients presenting with heart failure of uncertain etiology.

Cardiovascular MRI for the assessment of heart failure: focus on clinical management and prognosis

Cardiovascular MR (CMR) has an emerging role in the noninvasive diagnostic assessment of heart failure (HF). Different imaging sequences allow for a detailed assessment of cardiac morphology, function, myocardial perfusion, tissue characterization, and blood flow measurement. This article reviews the key applications of CMR in HF, with special focus on how CMR may influence the diagnostic and therapeutic approach of HF patients.

[The role of cardiovascular magnetic resonance imaging in the diagnosis and prognosis of patients with heart failure]

Cardiovascular magnetic resonance (CMR) imaging is a tomographic technique, which allows three-dimensional slice orientation without limitations from acoustic windows inherent to echocardiography. Further advantages of CMR are its high temporal and spatial resolution, its excellent soft tissue resolution and its high blood-to-tissue contrast. Cardiovascular magnetic resonance is currently the only imaging technique, which provides a comprehensive study of both structure and function of the heart as well as myocardial perfusion and viability. Moreover, post-processing of CMR images does not require any geometric assumptions as in echocardiography to determine ventricular dimensions. This is particularly important when evaluating ventricles of patients with chronic heart failure with severely altered morphology that may have regional variations in wall thickness and contractility at least in ischemic cardiomyopathy. The highly reproducible results of CMR imaging have turned this technique into a reference standard for the non-invasive assessment of ventricular dimensions, mass and function. In cases with indeterminate results of clinical, electrocardiographic and particularly echocardiographic findings CMR should be used early in the process of diagnosis of patients with heart failure. Not only can altered structure and degree of ventricular and valvular dysfunctions be accurately assessed but also regional perfusion deficits and/or myocardial scars are easily detected. For therapeutic and prognostic reasons a simple differentiation between ischemic and non-ischemic cardiomyopathy should be achieved as the first diagnostic step. In addition, the type and localization of the late gadolinium enhancement (LGE) phenomenon may aid in non-invasively differentiating the etiology of non-ischemic cardiomyopathy. CMR may also improve the assessment and extent of interventricular and intraventricular dyssynchrony in patients to be selected for cardiac resynchronization therapy (CRT). Lastly, the LGE phenomenon may provide independent prognostic information in patients with a CRT system implanted, as well as in patients with ischemic and non-ischemic cardiomyopathy. Thus, CMR imaging should be implemented early in the diagnostic process of patients with heart failure to significantly improve the speed and accuracy of diagnostic procedures, to control the effect of therapeutic measures, and to select patients with a limited prognosis by assessing the degree of ventricular dysfunction and the extent of myocardial scarring.

Clinical significance of papillary muscle late enhancement detected via cardiac magnetic resonance imaging in patients with single old myocardial infarction

BACKGROUND

Contrast-enhanced cardiac magnetic resonance imaging (MRI) can depict papillary muscle (PM) necrosis or fibrosis by late enhancement (LE) of PM, but its clinical significance in old myocardial infarction (OMI) has been little understood.

METHODS

Myocardial LE and PM-LE were detected with contrast imaging in 60 patients with OMI caused by a single culprit coronary artery lesion. Left ventricular (LV) morphology and function, mitral valve geometry, and severity of mitral regurgitation were also evaluated by cine imaging. Sphericity index was calculated for the assessment of LV remodeling.

RESULTS

PM-LE was detected in 32 of 60 (53.3%) OMI patients. Unilateral PM-LE was detected in 22 patients and bilateral PM-LE in 10 patients. Patients with bilateral PM-LE demonstrated more severe LV remodeling and functional mitral regurgitation than those with unilateral or no PM-LE (sphericity index; bilateral PM-LE, 1.60±0.15, unilateral PM-LE, 1.71±0.29, no PM-LE, 1.85±0.27, p≤0.05) (mitral regurgitation; bilateral PM-LE, 1.10±0.57, unilateral PM-LE, 0.41±0.73, no PM-LE, 0.54±0.84, p≤0.05). In cases of unilateral PM-LE, posteromedial PM-LE resulting from right coronary artery-related OMI was accompanied by less severe mitral regurgitation, while anterolateral PM-LE resulting from left coronary artery-related OMI was not associated with severity of mitral regurgitation.

CONCLUSIONS

More than half of patients with OMI showed unilateral or bilateral PM-LE, and bilateral PM-LE was closely related to more severe LV remodeling and functional mitral regurgitation.

Cardiovascular magnetic resonance of cardiomyopathies

Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with architectural abnormalities and mechanical dysfunction. Recent advances in our understanding of the genetics, pathophysiology, and natural history of these conditions has resulted in better diagnosis and management, leading to improvements in mortality. Major developments in imaging techniques, in particular contrast-enhanced MRI, now permit in vivo tissue characterization of the myocardium. Through defining disease severity, etiology, and to some extent in risk stratification, routine cardiovascular magnetic resonance evaluation of this group of patients provides essential information required in everyday clinical practice.

Delayed enhancement cardiovascular magnetic resonance as a novel technique to predict cardiac events in dilated cardiomyopathy patients

PURPOSE

Delayed enhancement cardiovascular magnetic resonance (DE-CMR) can detect cardiac scarring and has the potential to visualize the progression of myocardial remodeling. We determined whether DE-CMR can predict cardiac events in dilated cardiomyopathy patients.

MATERIALS AND METHODS

Transthoracic echocardiography, coronary arteriography, and DE-CMR studies were performed in 60 consecutive dilated cardiomyopathy (DCM) patients. Percent delayed enhancement (%DE) was determined as the ratio of the area showing delayed enhancement to the total myocardial area in three short-axis views. Patients were classified as advanced group (Group A) when %DE was 10% or higher, and as non-advanced group (Group NA) when %DE was less than 10%. The incidence of cardiac events and the clinical history were compared between Group A and Group NA.

RESULTS

There were 11 patients in Group A and 49 patients in Group NA. The incidence of cardiac events was significantly higher in Group A (36%; 4/11 patients) than in Group NA (2.0%; 1/49 patients) (log rank, p=0.0001).

CONCLUSION

DE-CMR is a useful tool to predict cardiac events in DCM patients.

Combined coronary and late-enhanced multidetector-computed tomography for delineation of the etiology of left ventricular dysfunction: comparison with coronary angiography and contrast-enhanced cardiac magnetic resonance imaging

Aims

To evaluate whether comprehensive evaluation of coronary anatomy and delayed enhancement (DE) by multidetector-computed tomography (MDCT) would allow determination of etiology of left ventricular dysfunction (LVD) as compared with coronary angiography (CA) and DE-magnetic resonance (CMR).

Methods and results

Seventy-one consecutive patients (50 males, 59 ± 16 years) with LVD (ejection fraction: 26 ± 11%) of unknown etiology underwent MDCT, LGE (late Gd-DTPA-enhanced)-CMR and CA. Patients were classified into four groups according to coronary artery disease (CAD) by CA and LGE-CMR patterns. Patients (n = 24) with CAD and transmural or sub-endocardial DE by CMR were considered having definite ischaemic LVD (group 1). Patients (n = 36) without CAD by CA and with no/atypical LGE-CMR were considered non-ischaemic LVD (group 2). Further we identified four patients with transmural DE but no CAD (group 3) and seven patients with CAD but no DE (group 4). On per-patient basis, combined coronary and DE-MDCT had excellent agreement (κ = 0.89; P < 0.001) with CA/LGE-CMR to classify patients into the same four groups. Sensitivity, specificity and accuracy of MDCT were 97, 92 and 94%, respectively for detecting patients with definite (group 1) or likely (groups 3 and 4) ischaemic LVD.

Conclusion

Combined coronary and DE-MDCT can accurately differentiate ischaemic vs. non-ischaemic etiology of LVD.